Eosinophils are granulocytes with distinctive cytoplasmic granules. To investigate the role of eosinophils in disease, these granules were isolated and their proteins were purified and characterized. At present, five proteins constitute the eosinophil granule; MBP, a homolog named MBP-2, EDN, ECP, and EPO. These proteins are distinctive markers for eosinophilia inflammation in a variety of human diseases. Furthermore, they are notable for their cytotoxic and cytostimulatory effects in vitro, and they have been associated with in vivo damage to cells and tissues. Over the past 20 years, we have developed the expertise to prepare and to use these unique eosinophil granule proteins. We have established the following techniques for these proteins: isolation, purification, characterization, generation and characterization of monoclonal and polyclonal antibodies, immunoassays, and immunohistochemical detection and localization in tissues. The laboratory core for this AADRC, the Eosinophil Granule Protein Laboratory Core, will prepare more reagents and perform analytical services for this entire AADRC. Specifically, we will isolate and purify the eosinophil granule proteins, which will then be used to examine the effects of these proteins on airway cells for Project 1, Regulation of Degranulation of Human Eosinophils, and for Project 2, Effects of Major Basic Protein on Human Airway Cells. Furthermore, body fluid specimens and cell culture supernatants will be monitored for the presence of eosinophils or for evidence of eosinophil degranulation activities with the unique and potent repertoire of specific polyclonal and monoclonal antibodies for these eosinophil granule proteins. These antibodies allow radioimmunoassays and two-site immunoassays of these proteins to be readily performed for Project 1 and Project 3, Eosinophilic Inflammation in Intrinsic Asthma. Moreover, this Core will use well-characterized antibodies for immunohistochemical staining to detect MBP, ECP, EDN, and EPO in tissue specimens generated in Project 1 and Project 2. Thus, the capabilities to quantitate, to stimulate with, and to localize the eosinophil?s distinctive granule proteins are intertwined with each of the three projects in the AADRC. This Eosinophil Granule Protein Core will serve as an essential and unique resource for the performance of this AADRC.